Shear resistance of reinforced laterized concrete beams without shear reinforcement

Abstract

This paper describes tests on shear resistance and deflection characteristics of 46 reinforced concrete beams without web reinforcement, 32 of the beams are laterized concrete containing laterites at 25%, 50%, 75% and 100% of total fine aggregate content, 6 beam have varying percentage reinforcement 1.81%, 2.28% and 2.75% while the remaining 8 beams are 1.21% reinforced normal concrete beams which are used as control. The aim of the test was to investigate the effects of the positioning of load, percentage laterite content and amount of longitudinal reinforcement on the shear strength of laterized concrete beams. Tests were performed on rectangular reinforced concrete beams of 150 × 150 mm cross-section with varying amounts of laterite content. The laterized concrete mix was 2:3:6 by weight with a water/cement ratio of 0.65. The shear-span/effective depth ratio was varied from 0.5 to 2.0 in steps of 0.5. Results indicate that: (a) the mode of failure does not depend on the percentage laterite content but depends mainly on the shear span; (b) the ultimate cracking load decreases with increase in the percentage laterite content. The ultimate shearing stress of laterized concrete was found to compare favourably with that specified in the Code of Practice CP 110 (1972). The ultimate shearing stress of laterized concrete increases with increase in the amount of longitudinal reinforcement there being approximately linear variation between the shear strength and percentage reinforcement. The results further show that the presence of laterite in the concrete improves its post-cracking ability and serviceability conditions due to high ductility, stiffness and superior crack control of lateritic content in comparison with plain concrete.